MOSCOW -- When agents from Russia's FSB intelligence service, burst into Paul Whelan's hotel room and pushed him to the floor, he said his first thought was that it might be a prank.
"I wasn't sure if it was real. I didn't know if friends of mine would have set up a gag or not," said Whelan, speaking from a prison camp in central Russia. "It obviously became, you know, quite real."
Nearly two years ago, the former U.S. Marine was detained in Russia and accused of being a spy. He became the improbable central character of a strange tale that Russia has presented as espionage, but which the United States and Whelan have said, in reality, is a hostage situation.
Whelan spoke to ABC News from prison, where he's serving a 16-year sentence on charges his family and U.S. officials say were fabricated in order to seize him as a political hostage. This is the first time he's spoken extensively to a journalist since his arrest in Moscow in late December 2018.
After his arrest, Whelan spent 18 months in pre-trial detention, essentially cut off from the outside world except for statements shouted to reporters in the few minutes they were allowed into the courtroom where he was being tried. In June, after a closed-door trial, Whelan was convicted and sent to a camp in Mordovia, a region about 300 miles east of Moscow known for its network of prisons.
"The guards call me 'Tourist,'" Whelan said.
Whelan, 50, now lives in a barracks at Correctional Colony-17, a crumbling former Gulag camp, originally built to hold prisoners during World War II. He's not separated from the other inmates, most of who are serving time for minor drug convictions he said, although others are convicted rapists and murderers.
"It's pretty grim. Quite dilapidated," Whelan said. "There's probably like 50 to 60 of us in the building. So we kind of live on top of each other."
The men sleep in rows of bunkbeds, share four toilets and there's no hot water except for when they are taken for their twice-weekly showers. Guards aren't posted within the barracks and the inmates essentially run things there themselves, Whelan said.
The prisoners awake at 6 a.m. for a 15-minute exercise routine before eight hours of required labor, making clothes in a workshop Whelan called "Dickensian." At night, because his name was added to a so-called escape watchlist, guards wake up Whelan every two hours.
Overall, though, Whelan said he's been treated reasonably well and is getting along with his cellmates.
"They've actually been quite welcoming," Whelan said. "Everybody works together as a team, so there is kind of a bit of a brotherhood."
"They all laughed when I got here," he continued. "Everybody knows that it's complete crap, and they laugh and say, 'Well, yeah, this is what the FSB does. It's obviously political.'"
Whelan and his family have said he is not a spy but a tourist crudely set up by the FSB or Federal Security Service, Russia's powerful domestic intelligence service, as the Kremlin sought leverage with the United States. Since Whelan's arrest, a second former Marine, Trevor Reed, was sentenced to nine years on dubious charges in a trial denounced by the U.S. as a sham.
A native of Michigan, Whelan was discharged from the Marines for bad conduct in 2008, after he was convicted of larceny. When he was arrested in Russia, Whelan was a global security executive for the auto parts supplier BorgWarner.
Whelan, an avid traveler who also has Irish, British and Canadian citizenship, is a self-described Russophile, and had visited Russia numerous times over the past decade, intrigued he said by the language and culture.
He was visiting Moscow in 2018 for a friend's wedding when he was arrested at the Metropol hotel, an upmarket hotel near the Kremlin.
"The whole thing was just like you see it on TV. You know, with the black masks. You had a guy videotaping it," Whelan said.
Russia has made the charges against Whelan secret, but according to his lawyers he's accused him of receiving a flash drive that contained classified materials.
Whelan said those charges are fabricated, part of a charade to frame him that included a longtime Russian friend, Ilya Yatsenko, delivering a flash drive to him moments before FSB agents burst into his room.
Whelan said he was introduced to Yatsenko online in 2007. Since then, Whelan said, he'd stayed many times with Yatsenko's family at their home in Sergeyev Posad, near Moscow, and he'd even brought his parents there to meet Yatsenko's.
Russian media reports have said Yatsenko was working as an FSB officer. Whelan said he believes that's false and that Yatsenko was a senior lieutenant in Russia's Border Service and a trainer at its academy -- "The people that stamp passports at the airport. ... He's not an FSB officer."
On the day of his arrest, Whelan recalled, Yatsenko had invited himself over and said he wanted to deliver a flash driving containing holiday photos and videos.
Whelan doesn't know why Yatsenko would be involved in his arrest plot.
"The only motive I can think of is trying to get promoted, you know, more money, a better apartment," said Whelan, adding with a laugh that "we're obviously not friends anymore."
ABC News' efforts to reach Yatsenko for comment were unsuccessful.
Whelan was taken to Moscow's Lefortovo jail, a former KGB prison, where he spent 18 months as the FSB tried to pressure him into a confession, he said, often interrogating him in the middle of the night.
"They kept saying, 'You know, Russia doesn't keep spies -- you'll be pardoned,'" Whelan said. "And of course, I said, 'No.' I said, "I'm not going to plead guilty to anything. I haven't done anything."
The FSB accused him of being a brigadier general for the U.S. Defense Intelligence Agency. Whelan said at first the agents interrogating him genuinely seemed to believe he was a spy, but that changed over time.
"They started to lighten up," Whelan said. "And I think that was because they realized I wasn't who at first they were saying I was. As they were going through the motions, they figured out it wasn't true, but the higher-level people were saying it was."
Despite his predicament, while speaking with ABC News Whelan appeared remarkably calm, at times seeming to find humor in his situation. He also doesn't seem to have lost his curiosity about Russia. On a few occasions, he said, he was brought to the FSB's feared headquarters, the Lubyanka, a place synonymous with Stalin-era torture.
"When I was there I asked if I could see the museum, because they've actually got a KGB museum there," Whelan said. "But they wouldn't go for it."
Whelan's eventual trial was rushed through in a month. After he was convicted, Whelan said the judge told him he knew the case was false but not to worry because he'd be released quickly.
"Right after he read the verdict, I went back to his chambers," Whelan said. "He was friendly. He actually told me on the day that I was sentenced that I would be sent home fairly quickly, that the Russian government had agreed to send me home. And it would be up to the two governments to work that out."
Russia has denied Whelan's charges are fabricated, but publicly Russian officials have repeatedly floated the idea of a possible exchange.
U.S. officials have said they believe Russia seized Whelan as a bargaining chip to swap for Russians imprisoned in the United States -- in particular, two men: Viktor Bout, an arms dealer jailed for 25 years on terrorism charges, and Konstantin Yaroshenko, a pilot sentenced to 20 years for drug smuggling.
Whelan said FSB officers immediately mentioned both men to him and that it was soon made clear Russia hoped for a trade.
"The night I was arrested, they asked me if I knew who those two people were," Whelan said.
Whelan said he didn't know why he specifically was targeted but said he believed that it could be linked to his work for BorgWarner and its business with KamAZ, a truck manufacturer part-owned by the Russian state defense conglomerate, Rostec, which was sanctioned by the U.S.
"I don't know why my name was chosen," Whelan said. "But I think this was partly sanctions retaliation."
He also said he believes Russia hoped to send a message to discourage U.S. law enforcement, which in recent years has aggressively targeted Russian criminals overseas and extradited them back to the U.S., even for crimes largely committed abroad.
"They don't like the fact that Russian citizens can be arrested in third-party countries, extradited to America and then have to serve time in American prisons," he said.
Whelan said he understands it's hard for the U.S. government to exchange him -- an American tourist taken hostage -- for two serious criminals.
It's seen as highly unlikely the U.S. will release Bout, perhaps the world's most famous arms dealer, who was the basis of the character for the Nicholas Cage film 'Lord of War'. But some experts have suggested that Yaroshenko might be more possible.
Despite Russian officials hinting at a swap though, according to Whelan's family, no negotiations are underway. Still, he remains optimistic.
"I don't think I'll be here that long -- the governments will work it out quickly," Whelan said. "I think it's a bit of an embarrassment for the Russian government because they've by now figured out that they've made a mistake. Like I said, you know, Mr. Bean being abducted on holiday. I don't think this is a situation they want going longer than it needs to."
In the meantime, Whelan doesn't feel unsafe at the camp. Two inmates, he believes, are acting as "minders," assigned to watch over him.
"I'm sure they've been told to treat me at least decently and to make sure nothing does happen to me," he said. "Because all you need is just some idiot from the Soviet army or the Russian army to say, 'Well, I'm going to get this American and do something stupid' to really cause a major international incident -- more so than already."